Question

A rectangular coil (0.20 m x 0.80 m) has 200 turns andis in a uniform magnetic field of 0.30 T. If the orientation of thecoil is varied through allpossible positions, themaximum torque on the coil by magnetic forces is 0.080 N-m. What isthe current in the coil?I'm not sure how to calculate the current in thecoil.
5.0 mA1.7 A8.3 mA1.0 A

Answer 1

Givennumber of turns in coil N = 200magnetic field B = 0.30 TArea of the coil A = 0.16 m²maximum torque τ =0.080N-m--------------------------------------------------------------------Mximum torque τ = (N iA)B( for maximumtorque Sin 90^o = 1 )the current in the coil i =τ / ( N A B )Substitute the values fori

Answer 2

We know that maximum torque on the coil is τ_max =NIAB
N = number of turns = 200
I = current
B = magnetic field = 0.3 T
τmax = 0.08 Nm
A = area of the coil = 0.2*0.8 = 0.16 m²
Then 0.08Nm= 200*I*0.16 m²*0.3T
Solve for current I